Lecture 2 - Epidemiology Primer

Question 1

Study of factors affecting occurrence of chronic and infectious disease

Answer 1

Epidemiology

Question 2

What is the transfer from mother to fetus?

Answer 2

Vertical (could also be congenital)

Question 3

Value most impacted by the prevalence of a disease in a population

Answer 3

Positive predictive value

Question 4

Formula used to calculate the sensitivity of an assay

Answer 4

TP/(TP+FN)

Question 5

Formula used to calculate the specificity of an assay

Answer 5

TN/(TN+FP)

Question 6

Formula used to calculate the positive predictive value of an assay

Answer 6

TP/(TP+FP)

Question 7

Formula used to calculate the negative predictive value of an assay

Answer 7

TN/(TN+FN)

Question 8

Rate of infection disease is calculated by what equation?

Answer 8

Actual cases (people who actually have the disease)/Potential cases (people at risk)

Question 9

Direct and Indirect are what forms of transmission of infectious diseases?

Answer 9

Horizontal

Question 10

In utero, during birth, colostrum, and suckled milk are what forms of transmission of infectious diseases?

Answer 10

Vertical

Question 11

What’s the difference between mortality and morbidity?

Answer 11

Mortality = death
Morbidity = illness

Question 12

Disease that has a relatively stable and expected incidence and prevalence within a geographic area (and population)

Answer 12

Endemic

Question 13

An abrupt and unexpected increase in the incidence of disease over endemic rates

Answer 13

Epidemic

Question 14

Spread of disease beyond continental boundaries

Answer 14

Pandemic

Question 15

Number of new cases of an infectious disease that occurs within a defined population over a defined period of time

Answer 15

Incidence

Question 16

Number of active cases at any given time (total)

Answer 16

Prevalence

Question 17

What happens to incidence and prevalence if: new effective treatment is initiated

Answer 17

Incidence: stays same
Prevalence: decreases

Question 18

What happens to incidence and prevalence if: new effective vaccine gains widespread use

Answer 18

Incidence: decreases
Prevalence: decreases

Question 19

What happens to incidence and prevalence if: number of deaths from the condition declines

Answer 19

Incidence: stays same
Prevalence: increases

Question 20

What happens to incidence and prevalence if: recovery is more rapid than it was 1 year ago

Answer 20

Incidence: stays same
Prevalence: decreases

Question 21

What type of study asks “What’s happening?” And collects data from a population to assess frequency of disease (and risk factors) at a particular point in time?

Answer 21

Cross-sectional study

Question 22

What does the cross-sectional study measure?

Answer 22

Disease prevalence

Question 23

What type of study asks, “What happened?” And compares a group of people with the disease (cases) to a group without disease (controls) in order to look for prior exposure or risk factors?

Answer 23

Case-control study

Question 24

What does the case-control study measure?

Answer 24

Odds ratio

• starts with disease
• proceeds from effect to cause

Question 25

What type of study asks, "who gets it?" And compares a group with a given exposure or risk factor to a group without such exposure to look to see if exposure affects the likelihood of the disease?

Answer 25

Cohort study

Question 26

What does the cohort study measure?

Answer 26

Relative risk - starts with exposure - proceeds from cause to effect

Question 27

Sensitivity is about what?

Answer 27

The disease

Question 28

Positive predictive values are about what?

Answer 28

The test

Question 29

Likelihood that a sick person tests positive (TP)

Answer 29

Sensitivity

Question 30

Likelihood a non-sick person tests negative (TN)

Answer 30

Specificity

Question 31

Likelihood that a positive test is found only in sick people (P's)

Answer 31

Positive predictive value

Question 32

Likelihood that a negative test is found only in non-sick people (N's)

Answer 32

Negative predictive value

Question 33

Diseased people with a positive test

Answer 33

Sensitivity (needs treatment)

Question 34

Nondiseased people with a negative test

Answer 34

Specificity

Question 35

Positive test results in diseased people

Answer 35

Positive predictive value

Question 36

Negative test results in nondiseased people

Answer 36

Negative predictive value

Question 37

TP/(TP+FN)

Answer 37

Sensitivity

Question 38

TN/(TN+FP)

Answer 38

Specificity

Question 39

TP/(TP+FP)

Answer 39

Positive predictive value

Question 40

TN/(TN+FN)

Answer 40

Negative predictive value

Question 41

What does prevalence of disease affect?

Answer 41

Only things with a positive

Question 42

What does prevalence impact?

Answer 42

PPV but doesn't affect the others

Question 43

What does high prevalence do to the PPV?

Answer 43

Improves PPV

Question 44

What does low prevalence do to PPV?

Answer 44

Harms PPV

Question 45

Positive screening tests are best suited for what patients?

Answer 45

Patients suspected of having the condition of interest